Written words are not composed merely of a random assignment of lines and dots. In all languages, words have a systematic internal structure. Some of these structures are purely form-based, as with the combination of lines that create letters in alphabetic languages (like the h, a, and t of hat), the grouping of letters that create syllables (like the chim and ney of chimney), and the recurrent combination of strokes found in Chinese (like the of and and the of and ). However, other structures, called morphemes, involve the interaction of form and meaning, and these are the focus of this chapter.